Efavirenz (By mouth)


Efavirenz (ef-a-VYE-renz)

Treats human immunodeficiency virus (HIV) infection. HIV causes acquired immune deficiency syndrome (AIDS). Efavirenz does not cure HIV or AIDS, but it may slow the progress of the disease when used in combination with other HIV medicines.

Brand Name(s)


When This Medicine Should Not Be Used

How to Use This Medicine

Capsule, Tablet

  • Take your medicine as directed. Efavirenz is used with other medicines to treat HIV infection. Make sure you take all of your medicines as your doctor has prescribed.
  • Take this medicine on an empty stomach, preferably at bedtime. Swallow this medicine whole with water. Do not break, crush, or chew the tablets.
  • If you or your child cannot swallow capsules or tablets
    • You may open the capsule and pour the contents into 1 to 2 teaspoons of soft food (such as applesauce, grape jelly, or yogurt).
    • For babies who cannot eat solid foods yet, you may also mix it with infant formula. Formula must be given through an oral dosing syringe.
    • This mixture must be given within 30 minutes.
    • After the mixed medicine has been taken, add a small amount of food or formula back to the empty container and gently stir to mix any medicine left in it. Swallow this mixture, too, to make sure you get all of the medicine that was in the capsule.
    • Do not eat anything else for 2 hours after taking this medicine mixed with food or formula.
  • Do not change or stop using this medicine without checking with your doctor first. When your supply of this medicine is running low, contact your doctor or pharmacist ahead of time. Do not allow yourself to run out of this medicine.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • There are many other drugs that may interact with efavirenz. These drugs can cause problems that are serious, even life-threatening. Make sure your doctor knows about all other medicines you are using. Tell your doctor if you change a dose of another medicine or stop taking another medicine. Your dose of efavirenz may need to be changed also.
  • Tell your doctor if you take rifampin (Rifadin®, Rifamate®, Rifater®) or voriconazole (Vfend®). Your dose may need to be changed.
  • Do not take Atripla® while you are being treated with this medicine. Atripla® also has efavirenz in it.
  • Make sure your doctor knows if you are using medicine to treat an infection (such as clarithromycin, rifabutin, Biaxin®, Mycobutin®), an estrogen hormone replacement or birth control pill, birth control implant (such as etonogestrel, Implanon®), or a blood thinner (such as warfarin, Coumadin®, Jantoven®). Tell your doctor if you are also using other medicine to treat HIV/AIDS (such as amprenavir, atazanavir, fosamprenavir, indinavir, lopinavir, maraviroc, raltegravir, ritonavir, saquinavir, Agenerase®, Crixivan®, Isentress®, Kaletra®, Lexiva®, Norvir®, Reyataz®, Selzentry®), or medicine to treat hepatitis C (such as boceprevir, telaprevir, Incivek®, Victrelis®).
  • Make sure your doctor knows if you also use medicine to treat seizures (such as carbamazepine, phenobarbital, phenytoin, Carbatrol®, Dilantin®, Tegretol®), medicine to treat fungus infections (such as itraconazole, ketoconazole, posaconazole, Nizoral®), or medicine to treat depression (such as bupropion, sertraline, Wellbutrin®, Zoloft®, Zyban®). Tell your doctor if you also use blood pressure medicine (such as diltiazem, felodipine, nicardipine, nifedipine, verapamil, Cardene®, Cardizem®), medicine to lower cholesterol (such as atorvastatin, pravastatin, simvastatin, Lipitor®, Vytorin®), medicine that weakens the immune system (such as cyclosporine, sirolimus, tacrolimus, Gengraf®, Neoral®, Protopic®, Rapamune®, Sandimmune®), or pain medicine (such as methadone, Dolophine®).
  • Alcohol, narcotic pain relievers, or sleeping pills may cause you to feel more lightheaded, dizzy, or faint when used with this medicine. Tell your doctor if you drink alcohol or use pain relievers or sleeping pills.

Warnings While Using This Medicine

  • You can harm your unborn baby if you use this medicine while you are pregnant. Use an effective form of birth control to prevent pregnancy. You should not become pregnant while you take this medicine and for 12 weeks after you stop taking it. If you think you have become pregnant, tell your doctor right away.
  • Birth control pills, implants, and other forms of hormonal birth control may not work as well while you are using efavirenz. Use an additional form of birth control such as condom, a diaphragm, contraceptive foam, or jelly while you take this medicine and for 12 weeks after you stop taking it.
  • Do not breastfeed. You can spread HIV or AIDS to your baby through your breast milk.
  • Tell your doctor if you have a history of liver disease or hepatitis B or C. Make sure your doctor knows if you have a history of seizures, mental illness, emotional problems, or drug abuse. Tell your doctor if you drink alcohol. Make sure your doctor knows about any other medical problems you currently have or have had in the past.
  • You might have mood or behavior changes with this medicine, such as feeling sad or hopeless, or getting upset easily. You could feel nervous or hostile. Some people become violent and want to hurt themselves or others. Call your doctor right away if you have any strange feelings, thoughts, or behaviors.
  • Tell your doctor if you get any type of skin rash, even a mild rash. Call your doctor right away if you have a rash with blisters, peeling skin, fever, mouth sores, red or irritated eyes, swelling of the face, muscle or joint pain, or muscle weakness.
  • This medicine might cause liver problems which are sometimes severe. Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, unusual tiredness or weakness, or yellow eyes or skin.
  • This medicine may increase the level of cholesterol and fats in your blood. Talk to your doctor if you have concerns.
  • Your immune system may get stronger when you start taking HIV medicines. Tell your doctor right away if you notice any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia, herpes, or tuberculosis.
  • This medicine will not keep you from giving HIV to others. Always practice safe sex, even if your partner also has HIV. Do not share needles or other items that may have blood or body fluids on them.
  • This medicine may make you dizzy or drowsy. Do not drive, use machines, or do anything else that could be dangerous until you know how this medicine affects you.
  • This medicine may cause changes in your body fat. Tell your doctor if you notice more fat in your upper back and neck or around the chest and stomach area. You may also lose fat from your legs, arms, and face.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Dark urine or pale stools, loss of appetite, yellow skin or eyes
  • Fast or pounding heartbeat
  • Lightheadedness or fainting
  • Seizures
  • Severe depression, anxiety, mood changes, hallucinations, problems dealing with anger, thoughts of hurting yourself or others
  • Sudden and severe stomach pain, nausea, vomiting

If you notice these less serious side effects, talk with your doctor:

  • Dizziness, headache
  • Fever or cough (in children)
  • Mild skin rash or itching
  • Tiredness
  • Trouble sleeping or concentrating, strange dreams
  • Weight gain around your neck, upper back, breast, face, or waist

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 8/4/2014

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